Canned Light Sources

global illumination algorithms, we pre-compute the outgoing light field of a given lamp and store away these
radiance values in a four-dimensional data structure. This discretized lighting information can later be used to
reconstruct the radiance emitted by the light source at every point in every direction. Instead of generating a global
illumination solution, a Canned Light Source could also be generated by resampling measured data or simply by
computing radiance values to achieve special effects.

A Canned Light Source can easily be integrated in standard global illumination algorithms, e.g. ray-tracing or
radiosity. Due to the huge amount of data, speed-up techniques such as shadow maps or adaptive downsampling
become mandatory for real world applications.

In addition to global illumination methods, it is also possible to use computer graphics hardware (projective
texture mapping, multi-pass rendering) for reconstructing the illumination from a Canned Light
Source.